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By Liguang Zhu, Yihua Han, Qingjun Zhang, Xiaoyan Wu, Pengcheng Xiao

The evolution of chemical composition, size, proportion, and morphology of the Al-Ti-Mg-O inclusions during the steelmaking process of Interstitial Free (IF) steel from the RH to the Continuous Casting (CC) slab were investigated by means of Auto-SEM. Results showed that many of Al2O3 and MgO-Al2O3 type inclusions are modified by TiOx, while most of their shapes are irregular due to the high melting temperature. The composition evolutions and melting characteristics of Al-Ti-Mg-O inclusions under different contents of [Al], [Ti] and [Mg] were estimated by using thermodynamic software Factsage 7.0. Results showed that estimated results are in good agreement with the analysis results of industrial samples. Both the Ti alloying and spontaneous enrichment would make a high Ti concentration environment that was in favor of the TiOx existence. Moreover, more TiOx component can modify MgO-Al2O3 spine inclusion into inclusions with a lower melting temperature.

Mar 1, 2018

By Matthew John M. Krane, Patrick E. Krane

This study examines the operations of the Cowper stoves attached to an iron blast furnace from a Second Law perspective. The exergetic efficiency of a 3-stove system operating at cyclic steady state is determined using a model accounting for the thermal, mechanical, and chemical flow exergies of the top gas and blast air, as well as the thermal exergy stored and released in the stoves. The analysis covers the heating and mixing of blast gas in one on-blast stove, and the combustion of top gas and its use to heat two on-gas stoves. The effect of different cycle times, and blast furnace operating conditions on the exergetic efficiency of the cycle is examined, and the optimal cycle time for different blast temperatures found. In addition, a study of the combustion parameters quantifies the advantages of using enriched oxygen in the combustors.

Mar 1, 2018

By Ze-Qiang Xie, Bai-hui Wang, Feng Chen, Ling-zhi Yang, Yu-feng Guo

In this paper, based on the big data in steelmaking process, equation about the relationship between steel composition (especially the oxygen content) and the element yield is established by using mathematical analysis method to analyze the factors influencing yield. Meanwhile, combining the alloy yield data-base that were established based on self-learning of historical data and computer technology in steelmaking process, a method of yield prediction of alloy elements is studied. To provide support for this method, alloying elements yield prediction software is developed to realize the rapid and intuitive site operation guidance, and to realize the precise control of dosage of alloy material.

Mar 1, 2017

By T. Thriveni, Ch. Ramakrishna, Ahn Ji Whan

Numerous reports and researches address the various environmental issues about the municipal solid waste incineration waste management of heavy metals and other particulate matters with the range of 10–2.5. Although in many developing and industrialization countries land fill with the disposal of municipal solid waste, open incineration has become a common practice. Bottom ash contains heavy metals including particulate matters. The investigation of size distribution for the heavy metals and particulate matters in the bottom ash is essential. However, ultra-fine particle size and heavy metal stabilization are the most important requirements for ecofriendly by products. There are wide variety commercial technologies available for monitoring PM 10, PM 2.5 and ultra-fine particles. In this paper, we reported the studies on physical and chemical characteristics of municipal solid waste incineration (MSWI) bottom ash containing particulate matter whose particulate sizes are lower than PM10, PM2.5 and heavy metal stabilization method by carbonation were investigated.

Mar 1, 2017

By Isadora Dias Perez, Denise C. Romano Espinosa, Flávia P. Cianga Silvas, Jorge A. Soares Tenório, Mónica M. Jiménez Correa

In view of the rising generation of wastewater containing metals, sustainable and clean techniques to recover them are being researched. This study investigated the adsorption of aluminum, cobalt, chromium, copper, iron (III), magnesium, manganese, nickel and zinc presents in a synthetic ef fluent by chelating ion exchange resin Dowex XUS43605. The resin was tested in columns experiments and was analyzed the flow rate (0.45, 0.66 and 1.11 BV/h), at pH 1.5 and 20 °C. After loading the column, the elution experiments occurred with 1 M of H2SO4 and 4 M of NH4O. The concentration of the metals in solution was obtained by X-ray fluorescence spectrometry energy dispersive (EDX). The results showed that the breakthrough experimental curves demonstrated that the main metals (aluminum, cobalt, manganese and zinc) were immediately broken through just after the initiation of the feeding, while the breakthrough of copper began later. Therefore, the study showed that the chelating resin could be used to treat contaminated effluents with metals.

Mar 1, 2017

By James Bennett, Jinichiro Nakano, Anna Nakano

Efficiency of the chemical looping combustion technology is adversely influenced by surface properties of oxygen carrier materials during oxidation–reduction process changes at elevated temperatures. In this work, natural hematite (Fe2O3) and alumina (Al2O3) supported Cu-spinel (CuFe2O4) oxygen carrier particles were isothermally exposed to redox gas cycles (air and 10 vol% CO–90 vol% Ar) at approximately 800 °C and studied using a high temperature confocal scanning laser microscope for real time alterations in surface morphology, roughness, and particle volume. 3D topological scans from each cyclic gas exposure indicated hematite particles exhibited noticeable volume expansion in reduction and shrinkage in oxidation, corresponding to respective phase transformations. Materials surface changes during the redox gas cycles are discussed.

Mar 1, 2017

By Tarek M. Hatem, Salah M. Bedair, Khaled H. Khafagy

Our understanding for intrinsic stresses and defects evolution in photovoltaic devices has became an essential part of new developments. In particular, Multi-Junction Photovoltaic (MJ-PV) modules depend on multi-layer structures that may suffer high dislocation-densities as a result of high lattice and thermal expansion coefficient mismatch. These defects limit the performance, reliability, and lifetime of PV devices. In the current study, a three-dimensional multiple-slip crystal-plasticity model and specialized finite-element formulations are used to investigate InGaN growth on Si substrates. The formulation is based on accounting for thermal and intrinsic stresses as a result of different processing conditions and microstructures. Furthermore, the formulation was used to investigate a recently developed technique, Embedded Void Approach (EVA), which can be used to address both the high density of defects and the cracking/bowing of InGaN growth on Si. The current work lays the groundwork for more extensive use of silicon in MJ-PV devices.

Mar 1, 2018

By Duclerc Fernandes Parra, Ademar B. Lugão, Nilton Lincopan, Fernanda Esposito, Vijaya Rangari

Polymeric hydrogels are natural or synthetic systems, which have gained interest due to their high biocompatibility with soft tissues. These types of hydrogels have been used for wound dressing as a drug delivery system. Here in this study the polymeric hydrogels based wound healing systems were prepared using poly (N-vinyl-2-pyrrolidone) (PVP), poly (ethylene glycol) (PEG), agar and neomycin drug followed by gamma irradiation to promote crosslinking and sterilization. The influence of irradiation process with 25 kGy dose was investigated. The gel fraction and maximum swelling were estimated using physicochemical methods and found about 95% gel fraction and 1100% swelling after 8 h of immersion. Neomycin released from hydrogel was carried out by Liquid Chromatography-Mass Spectrometry method and the drug concentration remained constant for 48 h. Hydrogel/neomycin exhibited antibacterial effects against Staphylococcus aureus. With these results, it can be inferred that hydrogel/neomycin is a suitable candidate for wound dressing.

Mar 1, 2018

By Yasuhiro Konishi, Norizoh Saitoh, Toshiyuki Nomura

This paper describes a new recycling method, based upon biotechnology, in order to extract platinum group metals (PGMs) from post-consumer products. The metal ion-reducing bacterium Shewanella algae was found to exhibit the ability to reduce and deposit PGMs. An integrated bioprocess using Shewanella bacteria to selectively recover Pd, Pt, and Rh from aqua regia leachates of spent automotive catalysts is demonstrated.

Mar 1, 2017

By Wei Han, Zhenwei Liu, Jianhong Yang, Qingwei Qin, Tiejun Chen, Zili Huang

The preparation of industrial ammonium molybdate from molybdenum concentrate was conducted according to the process of roasting—leaching—purification—precipitation—crystallization. The optimum technological conditions were determined: the roasting temperature was 680 degrees C, the roasting time was 2.5 h; in the leaching process the alkali excess coefficient was 1.2, the reaction temperature was 80 degrees C, the liquid-solid ratio was 3:1, the leaching time was 3 h; the amount of (NH4)2S added into the solution was 1.1 times of the theoretical amount, the temperature was 80-85 degrees C, and the terminal pH was 8.5-9 in the purification process; the density of the solution was 1.4-1.6 g/mL, the pH was 1.5-2 in the precipitation process; temperature of dissolution was controlled at 80-90 degrees C. The recovery of the preparation of ammonium molybdate can reach 85.18%.

Mar 1, 2017

By K. Morita, S. Ueda, Y. Matsuki

Tellurium has mainly been used as an alloying element for resulfurized free-machining steel. It globularizes MnS inclusions and improves both machinability and mechanical properties of such steel. This effect is quite sensitive to tellurium concentration.Therefore,its incorporation should be controlled accurately during the secondary refining process, using the thermodynamic properties of tellurium in molten iron. In the present study, Wagner’s interaction parameters of various elements on tellurium were experimentally evaluated by vapor-liquid equilibration, and the vapor pressure of tellurium was controlled using the transpiration method. The values obtained were compared with those of oxygen and sulfur, and they were found to be correlated with the standard Gibbs energy of formation of the corresponding oxides, sulfides, and tellurides.The results indicate that the relations described here could provide estimates of interaction parameters that have not been experimentally determined thus far by using available thermodynamic quantities.

Mar 1, 2017

By Zhengde Pang, Xue-wei Lv, Guibao Qiu, Chenguang Bai, Zhiming Yan

The viscous behavior of molten slags has played an essential role in determining the performance and productivity of the ironmaking process. In this paper, the viscosity and free running temperature in CaO-SiO2-Al2O3-9 mass% MgO-TiO2 slag has been measured at different content of Al2O3 and Al2O3/SiO2 ratio. In addition, the slags viscous activation energy has also been calculated. The results show that the TiO2 as a basic oxide content from 1 to 5 mass% can reduce the viscosity and free running temperature, and moderate content of TiO2 in high alumina blast furnace slag remains effective for reducing viscous activation energy and free running temperature.

Mar 1, 2018

By Mingming Zhang, Marcelo W. Andrade

The evolution of microstructure and mineral phases in iron ore sinters have been investigated by scanning electron microscope and QEMSCAN (Quantitative Evaluation of Minerals by Scanning Electron Microscopy). It was found that MgO, basicity and Al2O3 content play an important role in the formation of mineral phases and microstructure in sinter. The low Al2O3 (<2.0 wt%), medium MgO (2.0–2.5 wt%) and high basicity (>3.0) sinter showed higher low temperature degradation index (LTD) due to the presence of silico ferrites of calcium and aluminium (SFCA), and magnetite phase, and lower pore phase as compared to low basicity iron ore sinter.

Mar 1, 2017

By Lucio Fabio Cassiano Nascimento, Luis Henrique Leme Louro, Sérgio Neves Monteiro, Jheison Lopes dos Santos, Fernanda Santos da Luz, Fábio Oliveira Braga, Rubens Lincoln Santana Blazutti Marçal, Hugo Concolato de Oliveira Freitas, Édio Pereira Lima Júnior

Epoxy matrix composites reinforced with up to 10, 20 and 30 vol% of continuous and aligned natural mallow fibers and 30 vol% of mallow and jute hybrid fabric were for the first time ballistic tested as personal armor against class III 7.62 mm FMJ ammunition. The ballistic efficiency of these composites was assessed by measuring the dissipated energy and residual velocity after the bullet perforation. The results were compared with that in similar tests of aramid fabric (Kevlar™) commonly used in vests for personal protections. Visual inspection and scanning electron microscopy analysis of impact-fractured samples revealed failure mechanisms associated with fiber pullout, rupture and layers delamination. When compared to Kevlar™, the mallow fiber and hybrid fabric composite displayed practically the same ballistic efficiency. However, there is a reduction in both weight and cost, which makes both, mallow fiber and hybrid fabric composites, a promising material for personal ballistic protection.

Mar 1, 2018

By Huaqing Xie, Qingbo Yu, Qin Qin

A novel sorption-enhanced steam reforming (SESR) process of hot coke oven gas (HCOG) was proposed for tar removal and H2 amplification, and was studied with the comparison of conventional steam reforming (SCR) process. Both of the processes could remove tar effectively and improve the H2 amount in the COG obviously. For CSR process, after the temperature and the S/HCOG ratio reached 700 °C and 2.4 respectively, the H2 amplification factor kept 4.30 around, with its concentration less than 75%. However, for SESR process, the H2 amount and concentration get improved further, with the optimal temperature moving toward low temperature. At 600 °C and the S/HCOG ratio of 2.4, the H2 amplification factor and concentration could reach 4.91 and 97.55% respectively when the CaO/C ratio was 2.0. Under the respective optimal reforming conditions of the two processes, the energy consumption of the SESR process was lower than that of CSR process.

Mar 1, 2018

By Mario Sanchez, Jose Palacios, Fernando Parada

Carbon steels have less than 0.02% copper and have low atmospheric corrosion resistance. The addition of at least 0.20 wt% Cu improves this property. Also, 0.8 wt% Cu in steel shows a hardening potential for developing high strength corrosion resistant steels. Copper slags containing 42–45% of iron, silica and minor amounts of copper were used for producing Fe–Cu alloys by reducing the oxides contained in the slag to obtain a Fe-0.84 wt% Cu alloy, which could be suitable as feeding material to manufacture a corrosion resistance steel, and also would be an alternative for minimizing the copper industry ’s environmental impact, and to introduce the application of the Circular Economy concept to the natural resources exploitation, especially in countries where their economy is strongly based in mining and metallurgical extraction.

Mar 1, 2018

By Lucas de A. Pontes, Lázaro A. Rohen, F. V. Carlos Maurício, Janaina da Silva Vieira, Sergio Monteiro, Dhyemila de P. Mantovani, Frederico M. Margem, Anna C. C. Neves

The lower density of the lignocellulosic fibers such as the hemp fibers and the other natural ones is one of the characteristics that allow the scientists to obtain high levels of specific properties that when compared to the properties of ordinary reinforcements gives to the hemp fibers an advantage as a material with an expressive potential in the mechanical properties area. Then, the aim of this present work is to characterize the relative density of the hemp fiber related to the water using the pycnometry technique. This technique uses the pycnometer and it is divided in two steps. In the first step the correction factor and the moisture content of the fresh hemp fiber specimen and in the other step some weightings were done such as the dry specimen (g), empty pycnometer (g), pycnometer + water (g) and pycnometer + water + specimen (g) using a digital balance with a precision scale of 0.001 g of the bran INNERSCAN. Based on these measurement and calculations using some formulations already established in previous studies, the relative density of the hemp fiber found was around 1.393 g/cm3 and the moisture content around 7.1%.

Mar 1, 2017

By M. K. Ghosh, B. C. Tripathy, A. Baral

Present work is focused on the recovery of Mn as a value added product from the leach liquor of scrap lithium-ion batteries (LIBs) of mobile phones by the method of precipitation. The LIBs were crushed and bene ficiated by wet scrubbing method to separate cathodic material, plastic and metallic parts. The cathodic material was found to contain 11.3% Mn, 10% Co, 2.4% Cu and 2.4% Li. The cathodic material was processed for leaching under the optimized condition developed by our group at CSIR-NML. Solvent extraction method was used to extract acid using organic extractant Tris(2-ethylhexyl)amine (TEHA) in order to reduce the consumption of alkali required during precipitation studies. The acid free leach liquor was subjected to puri fication for removal of Fe, Li, Cu and Co as precipitate at different pH. Systematic precipitation studies were carried in batch and continuous mode to recover Mn as Mn(OH) 2 at pH *10 which was further roasted at 450 °C for 4 h to get pure Mn 3O4.

Mar 1, 2018

By Oscar Restrepo, Juan C. Nino, Henry A. Colorado

New and extraordinary physical-chemical properties of materials at nanoscale open up new applications for the building and infrastructure industry such as structural reinforcements, electronic properties and energy harvesting. Therefore the issues and risks associated with the manufacturing of nanomaterials are now of big concern due to the large volumes and typical processing involved in this industry. This paper presents a discussion and selected applications of nanotechnology in the construction and building materials: from metals and alloys, clay and minerals, ceramics, cement and concrete, asphalt, wood and composites, to finishing systems and some of the most used characterization techniques. Besides the progress in some areas, nanotechnology is just emerging in this field, with many challenges and opportunities, problems unsolved and business opportunities. A discussion regarding the potential health issues and risks of using nanomaterials for workers and the potential environment effects is included as well. New images and diagrams are presented and discussed.

Mar 1, 2018

By D. M. Fermino, C. G. Bastos Andrade, M. G. Fernandes, F. R. Valenzuela-Diaz

Treatments with high concentration solution of inorganic acid at temperatures under boiling point are a usual method for clay minerals structure modification. For many industrial uses bentonites must be cleared of impurities. In the present paper, a sample of Brazilian bentonite from Vitoria da Conquista, Bahia was modified by mild acid attack using hydrochloric acid under moderate conditions (90 °C, reaction times of 1, 6, 12, 18 and 24 h in close reactor, concentration of the aqueous solution of hydrochloric acid 1.5 M, acid solution/clay ratio of 1 g/10 mL). The attacked samples were characterized by CEC, XRF, SEM, EDS and Stereomicroscopy. The purpose of these attacks is to reduce the concentration of impurities with minimal damage in clay minerals structure. The modified bentonite presented good results and tends to be a good economic and environmental alternative to manufacturing products with high added value such as polymer/clay nanocomposites, cosmetics and medicines.

Mar 1, 2017